Molecular Mechanism in Regulation of Neuronal Dendritic Morphology

神经元树突形态调控的分子机制

基本信息

批准号：
07458203
负责人：
SHIRAO Tomoaki
金额：
$ 4.8万
依托单位：
Gunma University School of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

(1) In order to find out the relationships between drebrin and other actin associated proteins, drebrin, myosin, actin, toropomyosin, alpha-actinin, caldeson and gelsoin were purified, and various co-purification study with actin filament have been done. Drebrin binds to actin filaments at a stoichiometry of 1 : 5, with a dissociation constant (Kd) of 1.2x10^<-7>M.Drebrin does not exhibit any actin-nucleating, actin-severing or actin-capping activity, nor does it crosslink actin filaments. Drebrin did not affect the activity of gelsolin or actin binding activity of caldesmon and filamin, but strongly inhibited the actin binding activity of tropomyosin, and the actin binding and actin cross-linking activities of alpha-actinin and fascin. Drebrin has an inhibitory effect on actomyosin interation and might be an actin-linked regulatory protein of actomyosin interaction within neurons.(2) The morphological changes of dendritic spines of neurons have been postulated to participate in the expression of synaptic plasticity. We have examined the molecular mechanisms responsible for the changes in spine morphology, focusing on a protein that binds to actin filaments, drebrin, that is concentrated in neurons. We found that adult-type drebrin is localized in the dendritic spines in the forebrain of the rat, where it binds to the cytoskeleton of the spine. The drebrin-containing cytoskeleton consisted of drebrin, actin, myosin and gelsolin. In vitro, drebrin inhibited the movement of actin filaments on a glass surface that had been coated with myosin and reduced the actin-dependent ATPase activity of myosin. These results suggest that drebrin modulates the acto-myosin activity within spines and plays a role in the structure-based plasticity of synapses.

(1)为了找出drebrin与其他肌动蛋白相关蛋白的关系，纯化了drebrin、肌球蛋白、肌动蛋白、原肌球蛋白、α-肌动蛋白、caldeson和gelsoin，并与肌动蛋白丝进行了各种共纯化研究。 Drebrin 以 1:5 的化学计量与肌动蛋白丝结合，解离常数 (Kd) 为 1.2x10^<-7>M。Drebrin 不表现出任何肌动蛋白成核、肌动蛋白切断或肌动蛋白加帽活性，也不表现出任何肌动蛋白成核、肌动蛋白切断或肌动蛋白加帽活性。它交联肌动蛋白丝。 Drebrin不影响凝溶胶蛋白的活性或钙结合蛋白和细丝蛋白的肌动蛋白结合活性，但强烈抑制原肌球蛋白的肌动蛋白结合活性，以及α-肌动蛋白和肌成束蛋白的肌动蛋白结合和肌动蛋白交联活性。 Drebrin对肌动球蛋白相互作用具有抑制作用，可能是神经元内肌动球蛋白相互作用的肌动蛋白连接调节蛋白。(2)神经元树突棘的形态变化被认为参与突触可塑性的表达。我们研究了导致脊柱形态变化的分子机制，重点关注与肌动蛋白丝结合的蛋白质，即浓缩在神经元中的蛋白质。我们发现成人型drebrin位于大鼠前脑的树突棘中，在那里它与脊柱的细胞骨架结合。含drebrin的细胞骨架由drebrin、肌动蛋白、肌球蛋白和凝溶胶蛋白组成。在体外，drebrin 抑制了涂有肌球蛋白的玻璃表面肌动蛋白丝的运动，并降低了肌球蛋白的肌动蛋白依赖性 ATP 酶活性。这些结果表明，drebrin 调节棘内的肌动球蛋白活性，并在突触的基于结构的可塑性中发挥作用。